The present invention relates to no-scrub, no-wipe compositions for use in cleaning and maintaining showers and bathtubs and other surfaces and fixtures frequently exposed to moisture and soiling, especially involving hard water. The compositions contain an effective, non-streaking surfactant system, novel chelating salts, and optionally biocidal agents to inhibit mold, fungal, and bacterial growth.
A problem commonly encountered in bathrooms, particularly showers, tubs, and bathing facilities, is that, in the presence of hard water, lime (CaCO2) and soap scum build up on surfaces and fixtures. This buildup gives surfaces an unsightly appearance and creates a good breeding environment for mold and mildew, especially in conjunction with the moist, warm conditions usually present in such places. Further, mildew, lime, soap scum, and soil, once allowed to build up over time, are difficult to remove. The person who cleans such buildup is forced to use strong cleaners and bleaches that create harsh, irritating fumes when used in the close confines of the shower or bathroom.
The market has recognized the value of effective cleaning and maintenance products designed to prevent and/or eliminate these problems, as evidenced by sales growth of this new category of products. However, the current art provides systems that that sacrifice either cleaning ability, safety, or surface appearance. Specifically, there is a need for a product which provides effective cleaning and mold control at a neutral pH while also leaving the cleaned surface with a clear, glossy, streak-free appearance. Existing products which purport to achieve these objectives at neutral pH have been found to lack the ability to effectively clean heavy soil and/or to leave hazy films or streaks on the cleaned surface. Even those products which are marketed as xe2x80x9cstreak-freexe2x80x9d or xe2x80x9cno dull residuexe2x80x9d tend to leave behind iridescent films which are readily visible on chromed surfaces, and which often become hazy with extended drying (i.e., 1-24 hours).
The present invention not only solves the appearance problem (streaking, haziness) of the current art but also provides excellent cleaning at near neutral pH. In order to accomplish these goals, specific problems had to be solved by the inventor. First, although ethoxylated nonionic surfactants are generally preferred as the primary cleaning ingredient in compositions such as those of the present invention, these nonionic surfactants have the known drawback of drying to streaky or hazy films and of possibly damaging certain plastics with prolonged exposure. Second, it is known that the fatty soils found in soap scum are typically best removed by cleaning compositions at alkaline pH. In fact, the chelating agent most preferred for this type of cleaning, ethylenediamine tetraacetic acid (EDTA), is known to be most effective at moderately alkaline or even very alkaline pH (e.g., pH greater than 9-12).
The inventor has discovered that if specific blends of nonionic surfactants, other surfactants, and chelating agents, and optionally biocides, are combined, the user can perform a no-scrub, no-wipe, streak-free cleaning treatment of surfaces at or near a neutral pH.
To achieve these and other advantages, and in accordance with the purpose of the invention as embodied and broadly described herein, the present invention, in one aspect, provides an aqueous cleaning composition comprising at least one partial salt of ethylenediamine tetraacetic acid (EDTA) and a water-soluble amine; at least one alkyl polyglycoside surfactant; at least one alkyl ether carboxylate surfactant; and up to 0.5% by weight of an ethoxylated nonionic surfactant, relative to the total weight of the cleaning composition. The inventor has found that, surprisingly, effective cleaning, i.e., resulting in a clean surface with a streak-free, non-hazy appearance and minimal reoccurrence of mold and mildew stains, can be achieved by using partial salts of EDTA and water soluble amines coupled with at least one alkyl ether carboxylate surfactant, at least one alkyl polyglycoside surfactant, and a minimum amount of ethoxylated nonionic surfactants. The EDTA-amine partial salts act as chelating agents that are surprisingly more effective than EDTA salts previously used in the art, e.g., alkali metal EDTA salts such as disodium, trisodium, dipotassium, and tripotassium EDTA. Ethoxylated nonionic surfactants, typically used in cleaning compositions for their good cleaning properties, tend to leave streaks on the cleaned surfaces. Accordingly, they are used optionally and, if used, only in a small quantity in the present invention, allowing the inventive compositions to provide excellent streak-free cleaning but still performing like cleaners with higher levels of such surfactants.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
Reference will now be made in detail to the presently preferred embodiments of the present invention. The invention is drawn to an aqueous cleaning composition comprising at least one partial salt of EDTA and a water-soluble amine; at least one alkyl polyglycoside surfactant; at least one alkyl ether carboxylate surfactant; and up to 0.5% by weight of an ethoxylated nonionic surfactant, relative to the total weight of the cleaning composition. Preferably, the ratio of alkyl polyglycoside surfactant to total ethoxylated, ether carboxylate and other surfactants is at least 4:1.
The term xe2x80x9cpartial saltxe2x80x9d as used herein refers to a acidic compound, e.g., EDTA, in which the degree of neutralization is at least 1, i.e., at least one of the acid groups has been neutralized. In the present invention, the preferred partial salts of EDTA have a degree of neutralization of 2 to 3.
Water soluble amines useful in the present invention include, but are not limited to, those with a crystallization/melting point near or below ambient temperature. Preferably the water soluble amines are chosen from alkanolamines and morpholine. Alkanolamines useful in the present invention include, but are not limited to, 2-amino,2-methyl-1-propanol (isobutanolamine), monoethanolamine, diethanolamine, triethanolamine, aminoethylethanolamine, methyldiethanolamine, monoisopropanolamine, monobutanolamine, and diethanol isopropanolamine. Particularly preferred is monoisopropanolamine. The at least one EDTA-amine partial salt is present in the composition of the invention in an amount ranging from 0.1 to 10 percent, preferably 0.2 to 5 percent, by weight relative to the total weight of the composition.
The EDTA-amine partial salts are partially neutralized to provide products with pH values ranging from 5 to 9. The pH may also be maintained/adjusted by the presence of a buffering agent such as, but not limited to, water-soluble organic bases including amines, ethanolamines, aminoalcohols and morpholine.
Alkyl polyglycoside (APG) surfactants useful in the present invention include, but are not limited to, those having C6-C18 alkyl chains, particularly mixtures of such surfactants. Alkyl sources include natural fats and oils such as coconut oil. The amount of glycoside present generally ranges from 1-3 moles, preferably 1-2 moles per mole of fatty alkyl. APG surfactants that can be used in the present invention are available, e.g., from the Henkel Corp. under the GLUCOPON tradename: GLUCOPON 220, GLUCOPON 425, and GLUCOPON 600. These alkyl polyglycoside surfactants are nonionic. The at least one alkyl polyglycoside surfactant is present in the composition of the invention in an amount ranging from 0.1 to 4 percent, preferably 0.125 to 2 percent, relative to the total weight of the composition.
Alkyl ether carboxylated surfactants (AECs) useful in the present invention include, but are not limited to, compounds derived from alcohol ethoxylates and having the formula Rxe2x80x94Oxe2x80x94(EO)nxe2x80x94CH2xe2x80x94CO2M, wherein R is a straight or branched C6-C18 alkyl, preferably a C8-C14 alkyl, or an alkylaryl group, such as octylphenyl or nonylphenyl; EO denotes ethylene oxide; and M is either hydrogen or a metal ion. The amount of ethylene oxide varies according to the chain length of the alkyl group. Preferably, tile compounds used are derived from primary alcohol ethoxylates, but the AECs may be chosen from propylene tetramer derived alcohols, Guerbet alcohols, secondary alcohols and branched alcohols with smaller chain branches, especially methyl and ethyl branches. Alcohol alkoxylate carboxylates, based on multiple alkylene oxides such as ethylene oxide and propylene oxide, are also useful.
AECs which can be used in the present invention are available, e.g., from Hickson-DanChem Corp. under the name Neodox(trademark) Carboxylates; from Finetex under the name Surfine(trademark); from Clariant under the names Sandopan(trademark) and Sandosan(trademark); and from Albright and Wilson under the Empicol C(trademark) series.
The at least one alkyl ether carboxylated surfactant is present in the composition of the invention in an amount ranging up to 1 percent, preferably 0.0025 to 0.4 percent, relative to the total weight of the composition.
The ethoxylated nonionic surfactants useful in the present invention include, but are not limited to, traditional cleaning agents for hard surfaces such as alcohol alkoxylates, alkylene oxide (co)polymers, ethoxylated fatty acids, alkyl alkoxylates (including both ethylene and propylene oxide), alkylphenol ethoxylates, ethoxylated amines, and mixtures thereof. The alkyl chains range in length from C6-C,8, preferably C8-C14. These ethoxylated nonionic surfactants are present in an amount up to 5 percent, preferably ranging from 0.001 to 0.5 percent, and more preferably 0.0025 to 0.2 percent by weight relative to the total weight of the composition.
Additionally, the inventive composition may contain volatile solvents, preferably hydrophilic volatile solvents, including, but not limited to, alcohols and glycol ethers such as methoxypropanol, butoxyethanol, ethylene glycol ethers, and propylene glycol ethers. Ethylene glycol ethers are available from Dow Chemical""s DOWANOL E series and propylene glycol ethers from the DOWANOL P series. These volatile solvents are present in the composition of the invention in an amount ranging up to 15 percent, preferably from 2 to 10 percent, relative to the total weight of the composition.
The inventive composition may also contain nonvolatile co-solvents, including, but not limited to, alkyl pyrrolidones, citrate esters, organic carbonates, and terpenes. These nonvolatile co-solvents are present in the composition of the invention in an amount ranging up to 1 percent, preferably from 0.0025 to 0.1 percent, relative to the total weight of the composition.
Other optional ingredients are those known in the art to be useful in cleaning compositions, but which do not affect the final claimed properties of the present invention. Such ingredients include, but are not limited to, biocides, fragrances, peroxide bleaches, preservatives, soil-release agents, silicone surfactants, or fluorosurfactants.
Another aspect of the present invention is a method for cleaning a soiled surface to provide a clean surface which is substantially streak-free by applying to a soiled surface an aqueous cleaning composition as described above.